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%I #20 Aug 24 2023 02:31:32
%S 4,10,30,90,294,964,3304,11464,40584,145338,526638,1924378,7086598,
%T 26259388,97842104,366273464,1376854004,5194587924,19661846184,
%U 74637375132,284068160592,1083712790142,4143223406562,15871346734402,60907343008066,234122710710436
%N Number of monic irreducible polynomials over GF(4) of degree <= n.
%p with(numtheory):
%p b:= n-> add(mobius(d) *4^(n/d)/n, d=divisors(n)):
%p a:= n-> add(b(k), k=1..n):
%p seq(a(n), n=1..30); # _Alois P. Heinz_, Sep 23 2008
%t f[n_] := DivisorSum[n, MoebiusMu[#] * 4^(n/#) &] / n; Accumulate[Array[f, 26]] (* _Amiram Eldar_, Aug 24 2023 *)
%o (PARI) a(n)=sum(m=1, n, 1/m* sumdiv(m, d, moebius(d)*4^(m/d) ) ); /* _Joerg Arndt_, Jul 04 2011 */
%Y Partial sums of A027377. 4th column of A143328. - _Alois P. Heinz_, Sep 23 2008
%K nonn
%O 1,1
%A Gary L Mullen (mullen(AT)math.psu.edu) and Ken Hicks, Jan 06 2006
%E More terms from _Alois P. Heinz_, Sep 23 2008
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